Circuit arrangement for relay selectors in telephone systems



Feb. 9; V1932. M. LANGER Filed Oct. 7. 1929 fusi,

max Lenmar 1,844,256 CIRCUIT ARRANGEMENT FR RELAY SELECTORS IN TELEPHONE SYSTEMS 2 Sheets-Sheet 1 Feb. 9, 1932. M. LANGER 1,844,256

CIRCUIT ARRANGEMENT FOR RELAY SELECTORS IN TELEPHONE SYSTEMS Filed oct. '7. 1929 2 sneetssheet 2 F i E rz IF lez j, 2 e, "D an 1E AMA 22f #We 3 c1 I lex .IP/511m ITIUEHF'- 5X Langer the corresponding leads in Fig. 1.

Patented Feb. 9, 1932 UNITED STATES PATENT OFFICE MAX LANGER, 0F HERMSDORF, BERLIN, GERMANY; ASSIGNOR T0 SIEMENS & HALSKE AKTIENGESELLSCHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY CIRCUIT ABRANGEMENT FOR RELAY SELECTORS IN TEEIIHONE SYSTEMS Application am october 7.1929, serial No.

The present invention relates to a circuit arranvement for relay selectors, such as are used or example in telephone systems for connecting an incoming line with one of several outgoing lines. Different arrangements have already been proposed .for automatically selecting a free outgoing hne, wherein the number of the relays of the relay selector is equal to the number of out going lines. But arrangements are also already known, wherein the number of test relays of the relay selector is less than the number of outgoing lines, but this arrangement requires specially constructed' test relays, such as for example relays havlng their contacts operated in stages, polarized relays or the like. Now the object of the present invention is not to use any specially constructed relays and nevertheless to provide fewer of these relays than there are outgoing lines. This is achieved by'providing in the `test leads of the individual lines one or more windings of the test relays.

According to the `invention, furthermore, all outgoing lines are simultaneously tested upon the arrival of an impulse for initiating the setting up of a connection over the relay selector; this avoids having to provide special devices or making ready a free outgoing line.

Several methods of carrying out the invention are shown by way of example in the drawings. Fig. 1 shows the complete circuit of a relay type switch.- Fig. 2 shows a modification of the c lead or testing circuit of a relay switch such as shown in Fig. 1. Fig. 3 shows a further modification of the c lead of a relay switch such as shown in Fig. 1. In considering the two modifications it is to be understood that the a and b leads are arranged in the same manner as The designations applied to relays and relay contacts are uniform throughout the drawings.

In Fig. 1 is shown a'relay switch, which, when taken into use, connects the subscribers station T with a free one of seven reference is made.

397,784, and in Germany January 8, 1929.

provided three relays D, E, F, of these the relay D has one winding, while each of the relays E and F has three windings.

When the receiver is taken down at the subscribers station T to initiate a call, the following circuit is established for winding I of the calling relay R: earth, battery, winding I of relay R, contact 27 f, contact 13 e, contact 10 d, lead a, subscribers station T, lead b, contacts 9 d, 12 e, 25 f, earth. Relay R is operated and actuates its contacts 1 r to 7 1', inclusive. Thereby earth is applied to all outgoing c leads of the shown preselector; hence all accessible lines are simultaneously tested. If the line 2a, 2b, 2c be free, battery is present on the lead 2c, hence the followin circuit is established: battery, (not shown? at the lead 2c, contact 18 e, winding I of relay F, contact 1 1", winding I of relay D, contact 77', lead c, earth E7'. In this circuit are operated the relays D and F over their winding I and actuate their contacts. Relay D operates its contacts 8 d, 9 d, 10 d, and relay F operates the contacts 20 f, 21 f, 22 f, 23 f, 24 f, 25 f, 26 f, 27 f, 28 f. The switching over of these contacts interrupts the circuit of re-A lay R, whichfalls back. Contacts 1 1' to 7 r areopened. But there still exists the test circuit extending over lead 2 c as follows: battery at lead 2 c, contact 18 c,'winding I of relay F, `contact 22 f, winding I of relay D, contact 8 d, lead c, earth Er. The following speaking connection also exists: lead 2 a, contacts 14 e, 20 f, 10 d, lead a, subscribers staticn T, lead b, contacts 9 d, 21 f, 16 e, lead 2 When the connection is to be released, the battery applied to the lead2 0 is disconnected in some known manner, so that the relays D and F can be deenergized and the switch can return to the normal position.

In the Fig. 2 is shown the o lead or test circuit of a preselector, the calling relay of which is not disconnected after a call has been received, so that it remains energized. The switch also shows a device for incoming calls. The circuit of the a and b leads of the switch is the same as that in Fig. 1 to which When; the subscriber takes down his receiver toset up a connection tion a circuit is established from battery over v over a switch rovided with a c lead arranged according to ig. 2, a circuit is established for a winding I of a calling relay 1R which corresponds to the relay R, shown in Fig. 1. Relay 1R operates itsV contacts 1 r 1 to 6 1" 1, thereby the outgoing lines 1 c.' 1 to 7 c 1, inclusive, are tested at the same time. Idle lines are marked by battery on the C lead. If, for example the first line is idle when a call is initiated as above described, a circuit is established: battery (not shown), lead 1 c 1, winding II of relay 1E, contact 2 r 1, winding` I of relay 1F, contact 1 1 1, winding I of relay 1D, c lead, winding II of relay 1R, earth. Relays 1D, 1E, and 1F are operated in this circuit and relay 1R (corresponding to relay R of Fig. 1) is maintained energized. Referring now to the a and b leads shown in Fig. 1, it will be seen that the operation o1' relays 1D, 1E, and 1F completes the following speaking connection: lead 1a, contact 14e, contacty 20f, contact 10d, a lead, subscribers station T, b lead, contact 9d, Contact 21f, contact 16e, lead 1b. In case the first line is busy, ground on lead 1. c 1 will prevent the operation of the relays in the combination above described and a different line will be connected with. The combinations in which the relays operate in calls over different lines are as follows: line 2, relays 1F and 1D; line 3, relays 1E and 1D; line 4, relay 1D; line 5, relays 1E and 1F; line 6, relay 1E; and line 7, relay 1F. The original energizing circuit of the calling relay (1R) is openedk on the establishment of the connection with an idle line but the relay is maintained operated by its second winding which is energized in series with one or more of the connecting relays as above described.

It will be clear from the foregoing that the setting up of the connection takes place in the saine manner as already described for Fig. l, the only diiference being that the relay 1R receiving the call remains energized during the connection. When the calling subscriber hangs up his receiver to release the connection, the battery connected to the test lead is switched off in any known manner, thus interr yting the test circuit and de energizing the relays located therein. The swliltch is then again ready to receive another ca Incoming calls are received over the fourth line. On the receipt of an incoming connec the lead 4 c 1, over winding III of relay 1 R, which opposes the windings II and I of relay 1 R, over contacts 19 c 1, 22 f, winding I of relay1D,leadc,windingIIofrelay 1 R, earth. In this circuit relay 1 D is operated, but relay 1 R cannot be operated, because the vwinding III opposes the winding II ofthe relay. Relay 1 D, by switching over the contact 8 d 1 and the contacts corresponding to contacts 9 d and 10 d (Fig. 1), switches the incom A further example is shown in Fig. 3.

Here the test circuits instead of being established over the contact pyramids, is established by applying earth direct to the test relays located in the separate leads. Here again only the c leads are shown, because the a and Z) leads are connected in the same inanner as in Fig. 1.

When a call is initiated, calling relay R operates as before described and the contacts 1 1" to 7 r, inclusive, are actuated, thereby applying earth to each outgoing lead over the corresponding windings of the test relays. Here likewise a free line is designated bythe application of battery to the c lead. The energizing of the windings' of the test relays located in the test circuit causes their associated contacts to be actuated, hence the connection is established in the manner previously described. The combinations of relays operated for connecting up the various lines areexactly the same as described for Fig. 2. In the example according to Fig. 3 the calling relay R can be released after switching through has been eifected, because the test circuit, independently of the contacts of relay R is maintained only by the contactsof the test relays by means of the earth applied to the c lead.

Obviously circuits can also be conceived wherein the contacts 1 7 to 7 r in the circuit according to Fig. 3, instead of being operated by the calling relay R, are operated separately by some other means, so that when a certain contact is operated, only a particular line is switched through.

What is claimed is:

1. In a relay switching device for connecting an incomin line to an idle one of a plurality of outgoing trunks, switching relays less in number than the number of accessible trunks, and windings of one or more 'of said relays in the test conductor of each of said trunks.

2. In a trunk selecting switch having access to a plurality of outgoing trunks, a less -plurality of switching relays for connecting with an idle one of said trunks, and windings of one or more of said relays in the test conductor of each of said trunks.

3. In a trunk selecting switch having access to a plurality of outgoing trunks, a less plurality of switching relays for connecting with an idle one of said trunks, and means for simultaneously testing the busy or idle condition of ally of said trunks.

4. In a trunk selecting switch having access to a plurality of outgoing trunks, a less plurality of switching relays operable in various combinations to connect with a'n idle one of said trunks, each of said relays designating several of said trunks, a test conductorindividual to each trunk, and a winding of each relay in the test conductor of each trun designated by the relay.

5. In a trunk selecting switch having ac'- cess to outgoing trunks, a switching relay for connecting with an idle trunk, and a plurality of windings of said relay for simultaneously testing a plurality of said trunks for their idle or busy condition.

6. In a telephone system, a switching device terminating a line and having access to a plurality of outlets, means in said device for extending calls from said line to an idle one of said outlets, and circuit connections whereby calls to said line may be extended to said device over a particular one of said outlets.

7. In a telephone system, a switching device terminating a line and having access to a plurality of trunks, a line relay having two opposing windings, means for operating said relay over one winding to initiate the operation of said device responsive to a call from the line, and means including the two windings of said relay for preventing the operation of the relay on calls to said line.

8. In a relay trunk selecting switch in which the contacts are connected in stages in pyramid formation, relays for controlling the switching stages, and circuit arrangements whereby one relay controls contacts in two stages.

9. In a relay trunk selecting switch in which the contacts are connected in stages 'in pyramid formation, relays equal in number to the switching stages, and circuit arrangements whereby contacts in each switching stage beyond the first stage are controlled by a plurality of relays.

10. In a trunk selecting switch having access to a plurality of outgoing trunks, a test conductor for each trunk, a plurality of switching relays less in number than the number of trunks, means for connectin said relays to said test conductors to test t e trunks g for their idle orbu'sy condition, and means for energizing a combination of said relays to connect with a trunk tested and found idle.

11. In a trunk selecting switch having access to a plurality of outgoing trunks, a less plurality of switching relays for connecting with an idle trunk, and means responsive to the switch being taken into use for connecting said relays to said trunks to simultaneous- A ly test all of the trunks for their idle or busy ductor of a trunk and one or more of said relays.

13. In a trunk selecting switch having access to a plurality of outgoing trunks, a less plurality of switching relays for connecting with idle ones of said trunks, a test conductor for each trunk normally connected to one or more of said relays, and means responsivel to the switch being taken into use for completing a circuit for each test conductor and the relays connected thereto.

14. In a switching device having access to a plurality of outlets, a less plurality of switc ing relays, and means for operating two or more of said relays in series to connect with certain of said outlets.

15. In a switchin device having access to a plurality of outets, a less plurality of switching relays, means for operating said relays individually to connect with certain of said outlets, and means for operating two or more of said relays in series to connect with other of said outlets.

16. In a switching device having access to a plurality of outlets, a less plurality of switching relays each designating several of said outlets, windings for said relays, and a test circuit for each outlet including serially connected windings of each relay designating the outlet.

In witness whereof, I hereunto subscribe my name this 13th day of September, A. D.

MAX LANGER. 

